Pin tool assemblies for friction stir welding and apparatus and methods including the same

ABSTRACT

Pin tool assemblies for friction stir welding and apparatus and methods that include the pin tool assemblies. The pin tool assemblies include an outer member, an inner member, and a stop. The outer member includes an inner surface that defines an elongate internal cavity and an external shoulder that includes an opening to the elongate internal cavity. The inner member includes a welding end, extends at least partially within the elongate internal cavity, and projects from the opening such that the welding end is external the elongate internal cavity. The pin tool assembly is configured to permit motion of the inner member relative to the outer member. The stop defines a plurality of stop configurations. Each of the stop configurations restricts motion of the inner member relative to the outer member in a stop direction to define a corresponding stop distance between the welding end and the external shoulder.

RELATED APPLICATION

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/606,297, filed on Jan. 27, 2015 and entitled PINTOOL ASSEMBLIES FOR FRICTION STIR WELDING AND APPARATUS AND METHODSINCLUDING THE SAME, and the complete disclosure of which is incorporatedby reference.

FIELD

The present disclosure relates to pin tool assemblies and moreparticularly to pin tool assemblies for a friction stir weldingapparatus, to friction stir welding apparatus that include the pin toolassemblies, and/or to methods of utilizing pin tool assemblies.

BACKGROUND

Friction stir welding (FSW) is a solid-state process for joining twobodies. In FSW, a welding end of a pin tool assembly is rotated, broughtinto contact with the two bodies at a joint therebetween, and plungedinto the two bodies. This generates heat due to friction between thewelding end of the pin tool assembly and the two bodies, which softensthe two bodies. Rotation of the welding end then causes mixing of thematerials that form the two bodies. The pin tool assembly may betranslated along the joint, thereby joining, or welding, the two bodiesat the joint.

The welding end may be fixed relative to a remainder of the pin toolassembly (but still rotated relative to the two bodies). Under theseconditions, friction stir welding of the two bodies leaves a void space,or divot, at the end of a weld therebetween. This may be especially truewhen the joint is a circumferential joint. Alternatively, the weldingend of the pin tool assembly may be configured to retract into the pintool assembly, thereby controlling and/or regulating a depth ofpenetration of the welding end into the two bodies during friction stirwelding of the two bodies. This permits the pin tool assembly to weldmaterials of different and/or varying thickness (e.g., thicknesses thatvary along a length of the joint). Additionally or alternatively, thisalso permits the welding end to be retracted at the end of a weldbetween the two bodies, thereby permitting termination of the weldwithout leaving the void space.

While pin tool assemblies with retractable welding ends may be effectiveat friction stir welding various bodies together, it may be difficult toaccurately control and/or regulate the extent to which the welding endextends from and/or is retracted into the pin tool assembly, especiallywhen the pin tool assembly is subjected to the high applied forces thatoften are utilized in friction stir welding. Thus, there exists a needfor improved pin tool assemblies for friction stir welding and/or forfriction stir welding apparatus and/or methods that include the improvedpin tool assemblies.

SUMMARY

Pin tool assemblies for friction stir welding and apparatus and methodsthat include the pin tool assemblies are disclosed herein. The pin toolassemblies include an outer member, an inner member, and a stop. Theouter member includes an inner surface that defines an elongate internalcavity. The outer member also includes an external shoulder thatincludes an opening to the elongate internal cavity. The inner memberincludes a welding end and extends at least partially within theelongate internal cavity. The inner member projects from the openingsuch that the welding end is external the elongate internal cavity. Thepin tool assembly is configured to permit motion of the inner memberrelative to the outer member to vary a distance between the welding endand the external shoulder. The stop defines a plurality of stopconfigurations. Each of the stop configurations restricts motion of theinner member relative to the outer member in a stop direction to definea corresponding stop distance between the welding end and the externalshoulder. The restriction of motion occurs within the elongate internalcavity. The methods include methods of operating a friction stir weldingapparatus that includes the pin tool assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic representation of examples of a friction stirwelding apparatus that includes a pin tool assembly according to thepresent disclosure.

FIG. 2 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes a retraction stopthat defines a plurality of stop configurations.

FIG. 3 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes a retraction stopthat defines a plurality of stop configurations.

FIG. 4 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes a retraction stopthat defines a plurality of stop configurations.

FIG. 5 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes a retraction stopthat defines a plurality of stop configurations.

FIG. 6 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stopthat defines a plurality of stop configurations.

FIG. 7 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stopthat defines a plurality of stop configurations.

FIG. 8 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stopthat defines a plurality of stop configurations.

FIG. 9 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stopthat defines a plurality of stop configurations.

FIG. 10 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 11 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 12 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 13 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 14 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 15 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 16 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 17 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 18 is a schematic cross-sectional view of a pin tool assembly,according to the present disclosure, that includes an extension stop anda retraction stop that both define a respective plurality of stopconfigurations.

FIG. 19 is a schematic cross-sectional view of a portion of a pin toolassembly, according to the present disclosure, that includes an outeradjustment mechanism in the form of an outer threaded bushing.

FIG. 20 is a schematic cross-sectional view of a portion of a pin toolassembly, according to the present disclosure, that includes an inneradjustment mechanism in the form of an inner threaded bushing.

FIG. 21 is a schematic cross-sectional view of a portion of a pin toolassembly, according to the present disclosure, that includes an outeradjustment mechanism in the form of an outer pin and a plurality ofouter holes.

FIG. 22 is a schematic cross-sectional view of a portion of a pin toolassembly, according to the present disclosure, that includes an inneradjustment mechanism in the form of an inner pin and a plurality ofinner holes.

FIG. 23 is a flowchart depicting methods, according to the presentdisclosure, of operating a friction stir welding apparatus.

FIG. 24 is a flowchart depicting a method, according to the presentdisclosure, of operating a friction stir welding apparatus.

DESCRIPTION

FIGS. 1-24 provide examples of pin tool assemblies 100 according to thepresent disclosure, of friction stir welding apparatus 30 that mayinclude and/or utilize pin tool assemblies 100, and/or of methods200/250 of operating a friction stir welding apparatus. Elements thatserve a similar, or at least substantially similar, purpose are labeledwith like numbers in each of FIGS. 1-24, and these elements may not bediscussed in detail herein with reference to each of FIGS. 1-24.Similarly, all elements may not be labeled in each of FIGS. 1-24, butreference numerals associated therewith may be utilized herein forconsistency. Elements, components, and/or features that are discussedherein with reference to one or more of FIGS. 1-24 may be included inand/or utilized with any of FIGS. 1-24 without departing from the scopeof the present disclosure.

In general, elements that are likely to be included in a given (i.e., aparticular) embodiment are illustrated in solid lines, while elementsthat are optional to a given embodiment are illustrated in dashed lines.However, elements that are shown in solid lines are not essential to allembodiments, and an element shown in solid lines may be omitted from agiven embodiment without departing from the scope of the presentdisclosure.

FIG. 1 is schematic representation of examples of a friction stirwelding apparatus 30 that includes a pin tool assembly 100 according tothe present disclosure. Friction stir welding apparatus 30 also may bereferred to herein as an apparatus 30 and may include a drive structure40, an inner member translation structure 50, an anvil 60, a separationregulating structure 70, and/or a control structure 80. Apparatus 30 maybe adapted, configured, designed, and/or constructed to friction stirweld a workpiece 90 that includes two bodies 92 that define a joint 94therebetween.

During operation of apparatus 30, and as discussed in more detailherein, workpiece 90 may be located on anvil 60 and pin tool assembly100 may be rotated, such as via drive structure 40. A welding end 142 ofpin tool assembly 100 then may be plunged into workpiece 90. Frictiongenerated by relative motion between welding end 142 and workpiece 90may soften a portion of workpiece 90 that is proximal to welding end142, and rotation of welding end 142 may mechanically mix and/or combinebodies 92, thereby welding the bodies together. The pin tool assemblymay be translated along joint 94, thereby creating a longitudinal weldalong joint 94 and/or between bodies 92.

Pin tool assembly 100 includes an outer member 120, and inner member140, and a stop 160. Outer member 120 includes an inner surface 124 thatat least partially defines and/or at least partially bounds an elongateinternal cavity 126. In addition, outer member 120 includes and/ordefines an external shoulder 122 that may face toward workpiece 90, maybe configured to contact workpiece 90 during operation of apparatus 30,and/or may be configured to contact a surface of workpiece 90 that isopposed to anvil 60 during operation of apparatus 30. External shoulder122 includes an opening 128 to, or that extends into, elongate internalcavity 126.

Inner member 140 includes and/or defines welding end 142 of pin toolassembly 100 and extends at least partially within elongate internalcavity 126. In addition, inner member 140 projects from opening 128 suchthat welding end 142 is external to elongate internal cavity 126. Pintool assembly 100 is configured to permit at least limited motion ofinner member 140 relative to outer member 120, such as along alongitudinal axis 158 of inner member 140. This motion of inner member140 relative to outer member 120 may be utilized to vary a distance 138between welding end 142 and external shoulder 122.

Stop 160 is located at least partially, or even completely, withinelongate internal cavity 126 and defines a plurality of stopconfigurations, which are discussed in more detail herein. Each of theplurality of stop configurations restricts the motion of inner member140 relative to outer member 120 in a stop direction and defines acorresponding stop distance (i.e., distance 138) between welding end 142and external shoulder 122. Stop 160 may restrict the motion of innermember 140 relative to outer member 120 within elongate internal cavity126, such as via operatively interlocking and/or operatively engaging(or operatively engaging with) inner member 140 and outer member 120within elongate internal cavity 126.

Conventional friction stir welding apparatus may include a conventionalpin tool assembly that includes an outer member and an inner member butthat does not include and/or utilize stop 160. In such conventionalfriction stir welding apparatus, control and/or regulation of the motionof the inner member relative to the outer member (i.e., control and/orregulation of the distance between a welding end of the inner member andan external shoulder of the outer member) is accomplished solely by astructure, which may be similar to inner member translation structure50, that is distal from the welding end of the inner member and/or thatis external to an elongate internal cavity that may be defined by theouter member.

As discussed, friction stir welding may include application of largenormal forces to a workpiece by the pin tool assembly, and these largenormal forces may produce bending and/or deflection of the inner member,of the outer member, and/or of one or more other components of theconventional friction stir welding apparatus, thereby decreasing anaccuracy of control and/or regulation of the distance between thewelding end of the inner member and the external shoulder of the outermember that may be obtained utilizing the conventional friction stirwelding apparatus. While this decreased accuracy still may be sufficientto provide a desired level of control in many friction stir weldingapplications, it may be insufficient in others. As an example, aerospaceapplications may require very tight control and/or regulation of thedistance between the welding end and the external shoulder, and thesetight tolerances may not be achievable utilizing conventional frictionstir welding apparatus.

In contrast to conventional pin tool assemblies, pin tool assemblies 100according to the present disclosure include stop 160. As discussed, stop160 defines a plurality of stop configurations and also may be referredto herein as an adjustable stop 160. The plurality of stopconfigurations may include any suitable number of stop configurations.As examples, the plurality of stop configurations may include at least2, at least 3, at least 4, at least 5, at least 6, at least 8, at least10, at least 12, at least 14, at least 16, at least 18, or at least 20different discrete stop configurations, with each of the discrete stopconfigurations defining a corresponding stop distance (i.e., magnitudeof distance 138). As another example, the plurality of stopconfigurations may include an infinite number of different stopconfigurations that define an infinite number of corresponding stopdistances. Examples of stops 160 that define a plurality of discretestop configurations are discussed in more detail herein with referenceto FIGS. 21-22. Examples of stops 160 that define an infinite (orcontinuously variable) number of stop configurations are discussed inmore detail herein with reference to FIGS. 19-20.

When stop 160 is restricting the motion of inner member 140 relative toouter member 120, the plurality of stop configurations may includeand/or define a maximum extension configuration and a minimum extensionconfiguration. In the maximum extension configuration, distance 138 mayhave a maximum value. In the minimum extension configuration, distance138 may have a minimum value. A remainder of the plurality of stopconfigurations may be between the maximum extension configuration andthe minimum extension configuration.

Pin tool assembly 100 may be configured such that a difference betweenthe maximum value and the minimum value has any suitable magnitude. Asexamples, the difference between the maximum value and the minimum valuemay be at least 0.25 millimeter (mm), at least 0.5 mm, at least 0.75 mm,at least 1 mm, at least 2 mm, at least 3 mm, at least 4 mm, at least 5mm, at least 7.5 mm, and/or at least 10 mm. Additionally oralternatively, the difference between the maximum value and the minimumvalue also may be less than 20 mm, less than 15 mm, less than 10 mm,less than 8 mm, less than 6 mm, less than 5 mm, less than 4 mm, lessthan 3 mm, less than 2 mm, and/or less than 1 mm.

It is within the scope of the present disclosure that the stop directionmay include any suitable direction along longitudinal axis 158. As anexample, the stop direction may include and/or be a retraction direction172. Thus, stop 160 may limit and/or restrict retraction of inner member140 into outer member 120 (or into elongate internal cavity 126 and/orinto opening 128 thereof) and/or may limit and/or restrict motion ofwelding end 142 toward external shoulder 122, and/or may regulate aminimum distance between welding end 142 and external shoulder 122.Under these conditions, stop 160 also may be referred to herein as aretraction stop 170 and/or may define a plurality of different minimumdistances between welding end 142 and external shoulder 122. Morespecific examples of retraction stops 170 that may be included in and/orutilized with pin tool assembly 100 of FIG. 1 are discussed in moredetail herein with reference to FIGS. 2-5 and 1-18.

As another example, the stop direction may include and/or be anextension direction 182. Thus, stop 160 may limit and/or restrictextension of inner member 140 from outer member 120 (or from elongateinternal cavity 126 and/or from opening 128 thereof) and/or may limitand/or restrict motion of welding end 142 away from external shoulder122, and/or may regulate a maximum distance between welding end 142 andexternal shoulder 122. Under these conditions, stop 160 also may bereferred to herein as an extension stop 180 and/or may define aplurality of different maximum distances between welding end 142 andexternal shoulder 122. More specific examples of extension stops 180that may be included in and/or utilized with pin tool assembly 100 ofFIG. 1 are discussed in more detail herein with reference to FIGS. 6-18.

As yet another example, stop 160 may limit motion of inner member 140relative to outer member 120 in both retraction direction 172 andextension direction 182. Under these conditions, stop 160 may bereferred to herein as both retraction stop 170 and extension stop 180(or pin tool assembly 100 may be referred to herein as including bothretraction stop 170 and extension stop 180). More specific examples ofpin tool assemblies 100 that include both retraction stop 170 andextension stop 180 are discussed in more detail herein with reference toFIGS. 10-18.

In FIG. 1, stop 160 is shown in an overlapping relationship with bothouter member 120 and inner member 140 to illustrate that stop 160 may beat least partially formed by both outer member 120 and inner member 140.As an example, stop 160 may include an outer stop structure 162 and aninner stop structure 166. Outer stop structure 162 may be defined byouter member 120, may be defined by inner surface 124 of outer member120, and/or may be defined by a portion of outer member 120 that definesat least a portion of elongate internal cavity 126. Inner stop structure166 may be defined by inner member 140, may be defined by an externalsurface 144 of inner member 140, and/or may be defined by a portion ofinner member 140 that extends within elongate internal cavity 126. Morespecific examples of outer stop structure 162 and inner stop structure166 that may be included in and/or utilized with pin tool assemblies 100of FIG. 1 are discussed in more detail herein with reference to FIGS.2-22.

Stop 160 further may include an adjustment mechanism 190. Adjustmentmechanism 190 may be configured to be selectively moved, actuated,and/or adjusted to transition stop 160 among the plurality of stopconfigurations. More specific examples of adjustment mechanisms 190 thatmay be included in and/or utilized with stop 160 of FIG. 1 areillustrated in FIGS. 2-22 and discussed in more detail herein withreference thereto.

Inner stop structure 166 may include and/or be an inner flange 167 thatmay be defined by inner member 140. As perhaps illustrated more clearlyin FIGS. 2-13, inner flange 167 may extend radially from externalsurface 144 of inner member 140. It is within the scope of the presentdisclosure that inner flange 167 may be integral to, formed with, and/ormonolithic with inner member 140. Alternatively, it is also within thescope of the present disclosure that inner flange 167 may be operativelyattached to inner member 140.

Inner flange 167 may extend perpendicular to longitudinal axis 158 ofinner member 140. Inner flange 167 may include and/or define a weldingend-proximal surface 168 that may be at least substantiallyperpendicular to longitudinal axis 158 and/or that may face towardwelding end 142. This is illustrated in FIGS. 2 and 4-13. Inner flange167 additionally or alternatively may include and/or define a weldingend-distal surface 169 that may be at least substantially perpendicularto longitudinal axis 158 and/or that may face away from welding end 142.This is illustrated in FIGS. 2-6 and 8-13.

Inner flange 167 may extend from welding end-proximal surface 168 to adrive end 150 of inner member 140, as illustrated in FIG. 7. Drive end150 may be at least substantially opposed to welding end 142.Alternatively, inner flange 167 may extend from welding end-distalsurface 169 to welding end 142, as illustrated in FIG. 3. Alternatively,inner flange 167 may extend between welding end-proximal surface 168 andwelding end-distal surface 169, as illustrated in FIGS. 2, 4-6, and8-13.

When inner stop structure 166 includes inner flange 167, adjustmentmechanism 190 may include and/or be an outer adjustment mechanism 192that may be operatively attached to outer member 120. When stop 160 isretraction stop 170, and as illustrated in more detail in FIGS. 2-5 and10-13, outer adjustment mechanism 192 may be configured to operativelycontact welding end-distal surface 169 of inner flange 167 to restrictmotion of inner member 140 within elongate internal cavity 126 inretraction direction 172 (as illustrated in FIG. 1). Under theseconditions, outer adjustment mechanism 192 may be located betweenwelding end-distal surface 169 and drive end 150 of inner member 140.

When stop 160 is extension stop 180, and as illustrated in more detailin FIGS. 6-13, outer adjustment mechanism 192 may be configured tooperatively contact welding end-proximal surface 168 of inner flange 167to restrict motion of inner member 140 within elongate internal cavity126 in extension direction 182 (as illustrated in FIG. 1). Under theseconditions, outer adjustment mechanism 192 may be located betweenwelding end-proximal surface 168 and welding end 142 of inner member140.

Outer stop structure 162 alternatively may include and/or be one or moreouter flanges 163 that may be defined by outer member 120. As perhapsillustrated more clearly in FIGS. 14-18, outer flange 163 may extendradially from inner surface 124 of outer member 120. It is within thescope of the present disclosure that outer flange 163 may be integralto, formed with, and/or monolithic with outer member 120. Alternatively,it is also within the scope of the present disclosure that outer flange163 may be operatively attached to outer member 120.

Outer flange 163 may extend perpendicular to longitudinal axis 158 ofinner member 140. Outer flange 163 may include and/or define ashoulder-opposed surface 164 and/or a shoulder-facing surface 165.Shoulder-opposed surface 164 may be at least substantially perpendicularto longitudinal axis 158 and/or may face away from external shoulder122. Shoulder-facing surface 165 may be at least substantiallyperpendicular to longitudinal axis 158 and/or may face toward externalshoulder 122. This is illustrated in FIGS. 14-18.

Outer flange 163 may extend from shoulder-opposed surface 164 toexternal shoulder 122, as illustrated in FIGS. 14-17. Additionally oralternatively, outer flange 163 (or another outer flange 163) may extendfrom shoulder-facing surface 165 to a drive end 130 of outer member 120,as also illustrated in FIGS. 14-17. Drive end 130 may be opposed toexternal shoulder 122. Alternatively, outer flange 163 may extendbetween shoulder-opposed surface 164 and shoulder-facing surface 165, asillustrated in FIG. 18.

When outer stop structure 162 includes outer flange 163, adjustmentmechanism 190 may include and/or be an inner adjustment mechanism 196that may be operatively attached to inner member 140. When stop 160 isretraction stop 170, and as illustrated in more detail in FIGS. 14-18,inner adjustment mechanism 196 may be configured to operatively contactshoulder-facing surface 165 to restrict motion of inner member 140within elongate internal cavity 126 in retraction direction 172 (asillustrated in FIG. 1). Under these conditions, inner adjustmentmechanism 196 may be located between shoulder-facing surface 165 andexternal shoulder 122. When stop 160 is extension stop 180, and asillustrated in more detail in FIGS. 14-18, inner adjustment mechanism196 may be configured to operatively contact shoulder-opposed surface164 to restrict motion of inner member 140 within elongate internalcavity 126 in extension direction 182 (as illustrated in FIG. 1). Underthese conditions, inner adjustment mechanism 196 may be located betweenshoulder-opposed surface 164 and drive end 130.

Pin tool assembly 100 also may include a fixed stop 110. Fixed stop 110may not be adjustable and/or may not be configured to define a pluralityof stop configurations. Examples of fixed stop 110 are illustrated inmore detail in FIGS. 2 and 4-5. Therein, operative engagement betweeninner flange 167 and outer member 120 functions as a fixed extensionstop 112 for inner member 140. In FIGS. 2 and 4-5, stop 160 may bereferred to herein as restricting motion of inner member 140 relative toouter member 120 in a first stop direction (i.e., retraction direction172) and fixed stop 110 may be referred to herein as restriction motionof inner member 140 relative to outer member 120 in a second stopdirection (i.e., extension direction 182). The second stop direction maybe opposed to the first stop direction.

While FIGS. 2 and 4-5 illustrate fixed stop 110 in the form of fixedextension stop 112, it is within the scope of the present disclosurethat fixed stop 110 also may include and/or be a fixed retraction stop.Under these conditions, the first stop direction may be extensiondirection 182, and the second stop direction may be retraction direction172.

With reference to FIGS. 1-22, outer member 120 may include any suitablestructure that may define inner surface 124, may define elongateinternal cavity 126, may include external shoulder 122, may includeopening 128, and/or that may be configured to support compressive forcesthat may be applied thereto during operation of friction stir weldingapparatus 30. As examples, outer member 120 may include and/or be ametallic outer member, a tubular outer member, an at least substantiallytubular outer member, a hollow cylindrical outer member, and/or an atleast substantially hollow cylindrical outer member. With this in mind,elongate internal cavity 126 may include and/or be a cylindrical, or atleast substantially cylindrical, internal cavity. Additionally oralternatively, an external surface 123 of outer member 120 may becylindrical, or at least substantially cylindrical.

External shoulder 122 may include and/or define any suitable shape. Asan example, external shoulder 122 may be a planar external shoulder. Asanother example, external shoulder 122 may be a smooth externalshoulder. As yet another example, external shoulder 122 may includegrooves and/or may be a grooved external shoulder.

Inner member 140 may include and/or be any suitable structure that mayextend at least partially within elongate internal cavity 126, that mayinclude welding end 142, that may project from opening 128, that may beconfigured to move relative to outer member 120 to vary distance 138between welding end 142 and external shoulder 122 (as illustrated inFIG. 1), and/or that may be configured to support compressive forcesthat may be applied thereto during operation of friction stir weldingapparatus 30. As examples, inner member 140 may include and/or be ametallic inner member, a cylindrical inner member, and/or an at leastsubstantially cylindrical inner member.

As discussed, a portion of inner member 140 may project from elongateinternal cavity 126 and/or from opening 128 such that welding end 142 isexternal to elongate internal cavity 126. This portion of inner member140 may be perpendicular, or at least substantially perpendicular, toexternal shoulder 122.

Welding end 142 may include and/or define any suitable shape. As anexample, welding end 142 may be a planar welding end. As anotherexample, welding end 142 may be a smooth welding end. As yet anotherexample, welding end 142 may include grooves and/or may be a groovedwelding end.

Drive structure 40 may include and/or be any suitable structure thatmay, or may be utilized to, rotate any suitable portion of pin toolassembly 100, such as outer member 120 and/or inner member 140. This mayinclude rotation of pin tool assembly 100 about longitudinal axis 158 ofinner member 140. Examples of drive structure 40 include any suitablemotor, electric motor, pneumatic motor, and/or hydraulic motor.

As discussed in more detail herein, inner member 140 may be configuredto selectively translate relative to outer member 120, such as toselectively vary the distance between welding end 142 and externalshoulder 122. This selective translation may be accomplished by innermember translation structure 50. Inner member translation structure 50may include and/or be any suitable structure that may, or may beutilized to, selectively translate inner member 140 relative to outermember 120, such as to vary the distance between welding end 142 andexternal shoulder 122. This may include translation of inner member 140along longitudinal axis 158 and/or translation of inner member 140within elongate internal cavity 126. Examples of inner membertranslation structure 50 include any suitable motor, electric motor,pneumatic motor, hydraulic motor, linear motor, linear actuator, rackand pinion assembly, and/or lead screw and nut assembly.

Anvil 60 may be configured to support workpiece 90 during friction stirwelding of workpiece 90. This may include supporting workpiece 90 on ananvil surface 62 that may face toward welding end 142 and/or that may bedefined by anvil 60. The friction stir welding may include theapplication of significant normal forces to workpiece 90 by pin toolassembly 100, and anvil 60 may be configured to support workpiece 90 ina fixed, or at least substantially fixed, orientation relative to pintool assembly 100 despite these normal forces. Thus, anvil 60 mayinclude and/or be a rigid, or at least substantially rigid, anvil 60and/or a fixed, or at least substantially fixed, anvil 60. Anvil 60 mayinclude and/or be formed from any suitable anvil material, such as ametal.

Separation regulating structure 70 may include and/or be any suitablestructure that may be adapted, configured, designed, and/or constructedto control and/or regulate a distance between anvil surface 62 andexternal shoulder 122 and/or that may be adapted, configured, designed,and/or constructed to operatively translate anvil 60 (or workpiece 90,when present) and pin tool assembly 100 relative to one another. FIG. 1illustrates two separation regulating structures 70, one that isassociated with drive structure 40, inner member translation structure50, and/or pin tool assembly 100 and one that is associated with anvil60. Apparatus 30 may include either, or both, separation regulatingstructures 70 in any suitable configuration and/or combination. As anexample, a first separation regulating structure 70 may be configured toregulate the distance between anvil surface 62 and external shoulder 122(i.e., to move anvil surface 62 and/or external shoulder 122 in theZ-direction of FIG. 1). As another example, a second separationregulating structure 70 may be configured to operatively translate anvil60 and pin tool assembly 100 relative to one another in the X-Y plane ofFIG. 1. As yet another example, a single separation regulating structure70 may control relative motion between external shoulder 122 and anvil60 in the X, Y, and Z-directions. Examples of separation regulatingstructure 70 include any suitable motor, electric motor, pneumaticmotor, hydraulic motor, linear motor, linear actuator, rack and pinionassembly, lead screw and nut assembly, and/or X-Y table.

Control structure 80 may include any suitable structure that may beadapted, configured, designed, constructed, and/or programmed to controlthe operation of at least a portion of apparatus 30. This may includecontrol of drive structure 40, inner member translation structure 50,and/or separation regulating structure 70. As illustrated in dottedlines in FIG. 1, control structure 80 may include one or morecommunication linkages 82 that may provide communication between controlstructure 80 and drive structure 40, inner member translation structure50, separation regulating structure 70, and/or any other suitableportion of friction stir welding apparatus 30.

Examples of control structure 80 include an electronic controller, adedicated controller, a special-purpose controller, a computer, apersonal computer, a display device, a logic device, and/or a memorydevice. Control structure 80 also may be referred to herein ascontroller 80 and may be programmed to perform one or more algorithms toautomatically control the operation of at least a portion of apparatus30. This may include algorithms that may be based upon and/or that maycause control structure 80 to direct apparatus 30 to perform anysuitable portion of methods 200/250, which are discussed in more detailherein.

FIGS. 2-5 are schematic cross-sectional views of pin tool assemblies100, according to the present disclosure, that include a stop 160 in theform of a retraction stop 170 that defines a plurality of stopconfigurations. In FIGS. 2-5, inner stop structure 166 includes innerflange 167. In FIG. 2, inner flange 167 is operatively engaged withouter member 120, with outer member 120 functioning as fixed extensionstop 112. Conversely, and as illustrated in FIG. 4, inner flange 167 isoperatively engaged with outer adjustment mechanism 192, with outeradjustment mechanism 192 restricting retraction of inner member 140 andthereby functioning as retraction stop 170. As illustrated in FIG. 5,outer adjustment mechanism 192 may be selectively moved to change alocation of retraction stop 170, thereby changing (increasing) a minimumdistance between welding end 142 and external shoulder 122 that may beobtained prior to operative engagement between inner flange 167 andouter adjustment mechanism 192. FIG. 3 illustrates an alternative shapefor inner flange 167.

FIGS. 6-9 are schematic cross-sectional views of pin tool assemblies100, according to the present disclosure, that include a stop 160 in theform of an extension stop 180 that defines a plurality of stopconfigurations. In FIGS. 6-9, inner stop structure 166 includes innerflange 167. In FIG. 6, inner flange 167 is operatively engaged withouter adjustment mechanism 192, with outer adjustment mechanism 192restricting extension of extension of inner member 140 and therebyfunctioning as extension stop 180. In FIG. 8, inner member 140 has beenretracted from the configuration of FIG. 6, thereby separating innerflange 167 from outer adjustment mechanism 192. In FIG. 9, outeradjustment mechanism 192 has been selectively moved to change a locationof extension stop 180, thereby changing (increasing) a maximum distancebetween welding end 142 and external shoulder 122 that may be obtainedprior to operative engagement between inner flange 167 and outeradjustment mechanism 192. FIG. 7 illustrates an alternative shape forinner flange 167.

FIGS. 10-18 are schematic cross-sectional views of pin tool assemblies100, according to the present disclosure, that include two stops 160 inthe form of a retraction stop 170 and an extension stop 180. Retractionstop 170 defines a plurality of retraction stop configurations, and anextension stop 180 defines a plurality of extension stop configurations.

In FIGS. 10-13, inner stop structure 166 of pin tool assembly 100includes an inner flange 167. In FIG. 10, a single inner flange 167 isoperatively engaged with an outer adjustment mechanism 192 of extensionstop 180, thereby defining a maximum distance between welding end 142and external shoulder 122 for the illustrated configuration of outeradjustment mechanism 192 of extension stop 180. In FIG. 11, the singleinner flange 167 is operatively engaged with an outer adjustmentmechanism 192 of retraction stop 170, thereby defining a minimumdistance between welding end 142 and external shoulder 122 for theillustrated configuration of outer adjustment mechanism 192 ofretraction stop 170. In FIG. 12, outer adjustment mechanisms 192 ofextension stop 180 and retraction stop 170 have been selectively moved,thereby defining different minimum and maximum distances between weldingend 142 and external shoulder 122.

FIG. 13 illustrates an alternative form of pin tool assembly 100 inwhich inner member 140 includes two inner stop structures 166 in theform of two inner flanges 167. In FIG. 13, a single outer adjustmentmechanism 192 is located between the two inner flanges 167, andselective movement of the single outer adjustment mechanism 192 changesboth the maximum and minimum distances between welding end 142 andexternal shoulder 122.

In FIGS. 14-18, outer stop structure 162 of pin tool assembly 100includes one or more outer flanges 163. In FIG. 14, a first outer flange163, which defines a shoulder-opposed surface 164, is operativelyengaged with an inner adjustment mechanism 196, thereby defining amaximum distance between welding end 142 and external shoulder 122 forthe illustrated configuration of inner adjustment mechanism 196. In FIG.15, a second outer flange 163, which defines a shoulder-facing surface165, is operatively engaged with inner adjustment mechanism 196, therebydefining a minimum distance between welding end 142 and externalshoulder 122 for the illustrated configuration of inner adjustmentmechanism 196. In FIG. 16, inner adjustment mechanism 196 has beenselectively moved, thereby defining different minimum and maximumdistances between welding end 142 and external shoulder 122.

FIG. 17 illustrates an alternative embodiment of pin tool assembly 100that includes two inner adjustment mechanisms 196, with a first inneradjustment mechanism 196 being configured to operatively engageshoulder-facing surface 165 and forming a portion of retraction stop 170and a second inner adjustment mechanism 196 being configured tooperatively engage shoulder-opposed surface 164 and forming a portion ofextension stop 180. In FIG. 17, the two inner adjustment mechanisms 196may be configured for independent adjustment along a length of innermember 40, thereby permitting independent adjustment of the minimum andmaximum distances between welding end 142 and external shoulder 122.

FIG. 18 illustrates another alternative form of pin tool assembly 100.In FIG. 18, a single outer flange 163 extends from outer member 120 andbetween a first inner adjustment mechanism 196 and a second inneradjustment mechanism 196. The first inner adjustment mechanism 196 isconfigured to contact shoulder-opposed side 164 of outer flange 163,thereby functioning as extension stop 180 and defining a maximumdistance between welding end 142 and external shoulder 122. The secondinner adjustment mechanism 196 is configured to contact shoulder-facingside 165 of outer flange 163, thereby functioning as retraction stop 180and defining a minimum distance between welding end 142 and externalshoulder 122. Similar to FIG. 17, the two inner adjustment mechanisms196 may be configured for independent adjustment along the length ofinner member 40, thereby permitting independent adjustment of theminimum and maximum distances between welding end 142 and externalshoulder 122.

FIGS. 19-22 provide more specific examples of adjustment mechanisms 190that may be included in and/or utilized with pin tool assemblies 100according to the present disclosure. Adjustment mechanisms 190 may forma portion of any suitable stop 160, including any suitable retractionstop 170 and/or extension stop 180. It is within the scope of thepresent disclosure that any of the structures, components, and/orfeatures of adjustment mechanisms 190 of any of FIGS. 19-22 may beincluded in and/or utilized with any suitable pin tool assemblies 100 ofFIGS. 1-18. Similarly, any of the structures, components, and/orfeatures of pin tool assemblies 100 of FIGS. 1-18 may be included inand/or utilized with adjustment mechanisms 190 of any of FIGS. 19-22without departing from the scope of the present disclosure.

FIGS. 19-20 illustrate adjustment mechanism 190 in the form of athreaded bushing 188. Threaded bushing 188 may be configured to beselectively rotated to change a location of adjustment mechanism 190 andthereby to change the configuration of stop 160. Thus, and when stop 160includes threaded bushing 188, stop 160 may be referred to herein asdefining a continuous and/or infinite number of stop configurations.

In FIG. 19, threaded bushing 188 is an outer threaded bushing 193 thatdefines an outer adjustment mechanism 192, and outer stop structure 162includes an outer threaded region 174 that extends along inner surface124 of outer member 120. Under these conditions, outer threaded bushing193 may be configured to be threaded into outer threaded region 174 viarotation of outer threaded bushing 193 relative to outer member 120. Asillustrated, outer threaded region 174 may extend along a longitudinalaxis 158 of inner member 140 and/or of elongate internal cavity 126, andstop 160 may be configured to be transitioned among the plurality ofstop configurations via rotation of outer threaded bushing 193 relativeto outer member 120. As also illustrated in FIG. 19, an outer lockingstructure 175, such as an outer lock nut, may be configured to lockouter threaded bushing 193 at a desired location within outer threadedregion 174.

In FIG. 20, threaded bushing 188 is an inner threaded bushing 197 thatdefines an inner adjustment mechanism 196, and inner stop structure 166includes an inner threaded region 176 that extends along an externalsurface 144 of inner member 140. Under these conditions, inner threadedbushing 197 may be configured to be threaded into inner threaded region176 via rotation of inner threaded bushing 197 relative to inner member140. As illustrated, inner threaded region 176 may extend alonglongitudinal axis 158 of inner member 140 and/or of elongate internalcavity 126, and stop 160 may be configured to be transitioned among theplurality of stop configurations via rotation of inner threaded bushing197 relative to inner member 140. As also illustrated in FIG. 20, aninner locking structure 177, such as an inner lock nut, may beconfigured to lock inner threaded bushing 197 at a desired locationwithin inner threaded region 176.

FIGS. 21-22 illustrate adjustment mechanism 190 in the form of a pin 186and a plurality of holes 187 configured to receive pin 186. In FIGS.21-22 pin 186 may be configured to be selectively inserted into aselected hole 187 to change a location of adjustment mechanism 190 andthereby to change the configuration of stop 160. In addition, stop 160may be configured to be transitioned among the plurality of stopconfigurations via removal of pin 186 from a given hole 187 andinsertion of pin 186 into another hole 187. Thus, and when stop 160includes pin 186 and holes 187, stop 160 may be referred to herein asdefining a plurality of distinct, discrete, and/or spaced-apart stopconfigurations 160.

In FIG. 21, pin 186 and holes 187 define an outer adjustment mechanism192. Under these conditions, outer stop structure 162 includes holes 187that may be located at different locations along a length of outermember 120. As an example, and as illustrated, holes 187 may extend in ahelical fashion about outer member 120 and/or along a length of outermember 120. Holes 187 also may extend perpendicular, or at leastsubstantially perpendicular, to longitudinal axis 158. Pin 186 of outeradjustment mechanism 192 also may be referred to herein as an outer pin194. Similarly, holes 187 of outer adjustment mechanism 192 also may bereferred to herein as outer holes 195.

In FIG. 22, pin 186 and holes 187 define an inner adjustment mechanism196. Under these conditions, inner stop structure 166 may include holes187 that may be located at different locations along a length of innermember 140. As an example, and as illustrated, holes 187 may extend in ahelical fashion about inner member 140 and/or along a length of innermember 140. Holes 187 also may extend perpendicular, or at leastsubstantially perpendicular, to longitudinal axis 158. Pin 186 of inneradjustment mechanism 196 also may be referred to herein as an inner pin198. Similarly, holes 187 of inner adjustment mechanism 196 also may bereferred to herein as inner holes 199.

It is within the scope of the present disclosure that pin 186 may beconfigured for a press, or friction, fit within holes 187. Additionallyor alternatively, it is also within the scope of the present disclosurethat pin 186 may include and/or be a threaded pin 186, such as a setscrew. Under these conditions, holes 187 may include and/or be threadedholes 187, and threaded pin 186 may be configured to be threaded into aselected one of the plurality of threaded holes 187 via rotation ofthreaded pin 186. When pin 186 is a set screw, outer pin 194 also may bereferred to herein as an outer set screw 194 and/or inner pin 198 alsomay be referred to herein as an inner set screw 198. Similarly, and whenholes 187 are the threaded holes, outer holes 195 also may be referredto herein as outer threaded holes 195 and/or inner holes 199 also may bereferred to herein as inner threaded holes 199.

FIG. 23 is a flowchart depicting methods 200, according to the presentdisclosure, of operating a friction stir welding apparatus (FSWA).Methods 200 include locating a workpiece at 205, rotating a pin toolassembly at 210, and plunging a welding end of the pin tool assemblyinto the workpiece at 215. Methods 200 further include maintaining anexternal shoulder of the pin tool assembly in contact with the workpieceat 220, translating the welding end along a joint of the workpiece at225, and restricting motion of the welding end relative to the externalshoulder at 230. Methods 200 further may include adjusting a distancebetween the welding end and the external shoulder at 235.

Locating the workpiece at 205 may include locating the workpiece on ananvil of the FSWA. The workpiece may include two bodies that define thejoint therebetween. Rotating the pin tool assembly at 210 may includerotating the pin tool assembly relative to the workpiece, rotating thepin tool assembly with a drive structure of the FSWA, rotating an outermember of the pin tool assembly, rotating an inner member of the pintool assembly, rotating the external shoulder, and/or rotating thewelding end. The inner member may define the welding end of the pin toolassembly. The outer member may define the external shoulder of the pintool assembly. Examples of the pin tool assembly and of the drivestructure are discussed herein.

Plunging the welding end of the pin tool assembly into the workpiece at215 may include translating the welding end and the workpiece towardand/or into contact with one another. This may include operativelydeforming the workpiece with the welding end, heating the workpiece viafriction between the workpiece and the welding end, and/or mechanicallymixing the workpiece via rotation of the welding end. The plunging at215 may be performed utilizing a separation regulating structure,examples of which are discussed herein.

Maintaining the external shoulder of the pin tool assembly in contactwith the workpiece at 220 may include maintaining the external shoulderin contact with an anvil-opposed surface of the workpiece. This mayinclude controlling and/or regulating a normal force that is applied tothe workpiece by the pin tool assembly to maintain the shoulder incontact with the workpiece. The maintaining at 220 may includemaintaining during the rotating at 210, during the plunging at 215,and/or subsequent to the plunging at 215.

Translating the welding end along the joint of the workpiece at 225 mayinclude translating to friction stir weld the two bodies together. Thismay include mechanically mixing, or intermixing, a portion of each ofthe bodies that is proximal to the joint. The translating at 225 mayinclude translating during the rotating at 210, during the plunging at215, and/or during the maintaining at 220.

Restricting motion of the welding end relative to the external shoulderat 230 may include restricting with a stop and/or restricting in atleast one stop direction. The stop may define a plurality of stopconfigurations, and the restricting may include restricting within anelongate internal cavity that is defined by the outer member. Therestricting at 230 may include restricting during the rotating at 210,during the plunging at 215, during the maintaining at 220, and/or duringthe translating at 225. Examples of the stop are disclosed herein.

Adjusting the distance between the welding end and the external shoulderat 235 may include selectively adjusting the distance. This may includeadjusting to change a depth to which the welding end is plunged into theworkpiece and/or adjusting based upon a thickness of the workpiece. Theadjusting at 235 may include adjusting during the rotating at 210,during the plunging at 215, during the maintaining at 220, and/or duringthe translating at 225.

FIG. 24 is a flowchart depicting a method 250, according to the presentdisclosure, of operating a friction stir welding apparatus. Methods 250include determining a desired stop configuration at 255 and adjusting astop configuration at 260.

Determining the desired stop configuration at 255 may includedetermining the desired stop configuration from a plurality of differentand/or distinct stop configurations for a pin tool assembly of the FSWA.The determining at 255 may be based upon any suitable criteria and/ormay be accomplished in any suitable manner. As an example, thedetermining at 255 may be based, at least in part, on a thickness of aworkpiece that is to be friction stir welded by the FSWA.

Adjusting the stop configuration at 260 may include adjusting the stopconfiguration of the pin tool assembly by changing a location of anadjustment mechanism of the pin tool assembly. The pin tool assembly mayinclude an outer member, which defines an elongate internal cavity andan external shoulder, and an inner member, which extends at leastpartially within the elongate internal cavity and defines a welding end.The welding end may project from the elongate internal cavity via anopening that is defined within the external shoulder, and the desiredstop configuration may correspond to a desired distance between thewelding end and the external shoulder.

Changing the location of the adjustment mechanism may include modifyinga relative orientation at which the inner member and the outer memberoperatively couple with one another within the elongate internal cavityvia the adjustment mechanism. As an example, the changing the locationmay include rotating a threaded busing of the pin tool assembly. Asanother example, the changing the location may include locating a setscrew of the pin tool assembly within a selected one of a plurality ofthreaded holes of the pin tool assembly.

Illustrative, non-exclusive examples of inventive subject matteraccording to the present disclosure are described in the followingenumerated paragraphs:

A1. A pin tool assembly for a friction stir welding apparatus, theassembly comprising:

optionally, an outer member including an inner surface that defines anelongate internal cavity, wherein the outer member further includes anexternal shoulder, and further wherein the external shoulder includes anopening to the elongate internal cavity;

an inner member that includes a welding end, wherein the inner memberextends at least partially within the elongate internal cavity andprojects from the opening such that the welding end is external theelongate internal cavity, and further wherein the pin tool assembly isconfigured to permit motion of the inner member relative to the outermember to vary a distance between the welding end and the externalshoulder; and

a stop that defines a plurality of stop configurations, wherein each ofthe plurality of stop configurations restricts, within the elongateinternal cavity, the motion of the inner member relative to the outermember in a stop direction and defines a corresponding stop distancebetween the welding end and the external shoulder.

A2. The assembly of paragraph A1, wherein the stop is an adjustablestop.

A3. The assembly of any of paragraphs A1-A2, wherein the plurality ofstop configurations includes a plurality of discrete stop configurationsthat includes at least 2, at least 3, at least 4, at least 5, at least6, at least 8, at least 10, at least 12, at least 14, at least 16, atleast 18, or at least 20 discrete stop configurations that define acorresponding plurality of different stop distances.

A4. The assembly of any of paragraphs A1-A3, wherein the plurality ofstop configurations includes an infinite number of different stopconfigurations that define an infinite number of different stopdistances.

A5. The assembly of any of paragraphs A1-A4, wherein, when the stop isrestricting the motion of the inner member relative to the outer member,the plurality of stop configurations includes a maximum extensionconfiguration, in which the distance between the welding end and theexternal shoulder has a maximum value, and a minimum extensionconfiguration, in which the distance between the welding end and theexternal shoulder has a minimum value, and further wherein a remainderof the plurality of stop configurations is between the maximum extensionconfiguration and the minimum extension configuration.

A5.1 The assembly of paragraph A5, wherein a difference between themaximum value and the minimum value is at least one of at least 0.25millimeter (mm), at least 0.5 mm, at least 0.75 mm, at least 1 mm, atleast 2 mm, at least 3 mm, at least 4 mm, at least 5 mm, at least 7.5mm, or at least 10 mm.

A5.2 The assembly of any of paragraphs A5-A5.1, wherein a/the differencebetween the maximum value and the minimum value is at least one of lessthan 20 millimeters (mm), less than 15 mm, less than 10 mm, less than 8mm, less than 6 mm, less than 5 mm, less than 4 mm, less than 3 mm, lessthan 2 mm, or less than 1 mm.

A6. The assembly of any of paragraphs A1-A5.2, wherein the stop includesa retraction stop.

A6.1 The assembly of paragraph A6, wherein the retraction stop isconfigured to limit retraction of the inner member into the elongateinternal cavity and thereby to define a corresponding minimum distancebetween the welding end and the external shoulder.

A6.2 The assembly of any of paragraphs A6-A6.1, wherein the stopdirection is a retraction direction.

A7. The assembly of any of paragraphs A1-A6, wherein the stop includesan extension stop.

A7.1 The assembly of paragraph A7, wherein the extension stop isconfigured to limit extension of the inner member from the opening andthereby to define a corresponding maximum distance between the weldingend and the external shoulder.

A7.2 The assembly of any of paragraphs A7-A7.1, wherein the stopdirection is an extension direction.

A8. The assembly of any of paragraphs A1-A7.2, wherein the stop isan/the extension stop, and further wherein the pin tool assemblyincludes a/the retraction stop.

A9. The assembly of any of paragraphs A1-A8, wherein the stop includes:

(i) an outer stop structure that is defined by the outer member, andoptionally by a portion of the outer member that defines a portion ofthe elongate internal cavity; and

(ii) an inner stop structure that is defined by the inner member, andoptionally by a portion of the inner member that extends within theelongate internal cavity.

A9.1 The assembly of paragraph A9, wherein the inner member defines aninner flange that extends radially from an external surface of the innermember, and further wherein the inner stop structure includes the innerflange.

A9.1.1 The assembly of paragraph A9.1, wherein the inner flange isintegral to the inner member.

A9.1.2 The assembly of any of paragraphs A9.1-A9.1.1, wherein the innerflange extends perpendicular to a longitudinal axis of the inner member.

A9.1.3 The assembly of any of paragraphs A9.1-A9.1.2, wherein the innerflange defines a welding end-proximal surface that faces toward thewelding end.

A9.1.3.1 The assembly of paragraph A9.1.3, wherein the weldingend-proximal surface extends perpendicular to a/the longitudinal axis ofthe inner member.

A9.1.3.2 The assembly of any of paragraphs A9.1.3-A9.1.3.1, wherein theinner flange extends from the welding end-proximal surface to a driveend of the inner member that is opposed to the welding end.

A9.1.4 The assembly of any of paragraphs A9.1-A9.1.3, wherein the innerflange defines a welding end-distal surface that faces away from thewelding end.

A9.1.4.1 The assembly of paragraph A9.1.4, wherein the weldingend-distal surface extends perpendicular to a/the longitudinal axis ofthe inner member.

A9.1.4.2 The assembly of any of paragraphs A9.1.4-A9.1.4.1, wherein theinner flange extends from the welding end-distal surface to the weldingend.

A9.1.4.3 The assembly of any of paragraphs A9.1.4-A9.1.4.2, wherein theinner flange extends between the welding end-distal surface and a/thewelding end-proximal surface of the inner flange.

A9.1.5 The assembly of any of paragraphs A9.1-A9.1.4.3, wherein the stopfurther includes an outer adjustment mechanism that is operativelyattached to the outer member.

A9.1.5.1 The assembly of paragraph A9.1.5, wherein the stop is a/theretraction stop, and further wherein the outer adjustment mechanism isconfigured to operatively contact a/the welding end-distal surface ofthe inner flange to restrict motion of the inner member within theelongate internal cavity in a/the retraction direction.

A9.1.5.2 The assembly of any of paragraphs A9.1.5-A9.1.5.1, wherein thestop is a/the retraction stop, and further wherein the outer adjustmentmechanism is located between a/the welding end-distal surface of theinner flange and a/the drive end of the inner member that is opposed tothe welding end of the inner flange.

A9.1.5.3 The assembly of any of paragraphs A9.1.5-A9.1.5.2, wherein thestop is a/the extension stop, and further wherein the outer adjustmentmechanism is configured to operatively contact a/the weldingend-proximal surface of the inner flange to restrict motion of the innermember within the elongate internal cavity in a/the extension direction.

A9.1.5.4 The assembly of any of paragraphs A9.1.5-A9.1.5.3, wherein thestop is a/the extension stop, and further wherein the outer adjustmentmechanism is located between a/the welding end-proximal surface of theinner flange and the welding end of the inner member.

A9.1.5.5 The assembly of any of paragraphs A9.1.5-A9.1.5.4, wherein theouter adjustment mechanism includes an outer threaded bushing, whereinthe outer stop structure includes an outer threaded region that extendsalong the inner surface of the outer member, and further wherein theouter threaded bushing is configured to be threaded into the outerthreaded region via rotation of the outer threaded bushing relative tothe outer member.

A9.1.5.5.1 The assembly of paragraph A9.1.5.5, wherein the threadedregion extends along a longitudinal axis of the elongate internalcavity.

A9.1.5.5.2 The assembly of any of paragraphs A9.1.5.5-A9.1.5.5.1,wherein the stop is configured to be transitioned among the plurality ofstop configurations via rotation of the outer threaded bushing relativeto the outer member.

A9.1.5.5.3 The assembly of any of paragraphs A9.1.5.5-A9.1.5.5.2,wherein the stop further includes an outer locking structure configuredto lock the outer threaded bushing at a desired location within theouter threaded region, optionally wherein the outer locking structureincludes an inner lock nut.

A9.1.5.6 The assembly of any of paragraphs A9.1.5-A9.1.5.5.3, whereinthe outer adjustment mechanism includes an outer pin, wherein the outerstop structure includes a plurality of outer holes that is configured toreceive the outer pin, and further wherein the outer pin is configuredto be inserted into a selected one of the plurality of outer holes.

A9.1.5.6.1 The assembly of paragraph A9.1.5.6, wherein the outer pin isan outer set screw, wherein the plurality of outer holes is a pluralityof outer threaded holes, and further wherein the outer set screw isconfigured to be threaded into a selected one of the plurality of outerthreaded holes via rotation of the outer set screw relative to the outermember.

A9.1.5.6.2 The assembly of any of paragraphs A9.1.5.6-A9.1.5.6.1,wherein the plurality of outer holes extends perpendicular, or at leastsubstantially perpendicular, to a/the longitudinal axis of the elongateinternal cavity.

A9.1.5.6.3 The assembly of any of paragraphs A9.1.5.6-A9.1.5.6.2,wherein the stop is configured to be transitioned among the plurality ofstop configurations via removal of the outer pin from a given outer holeof the plurality of outer holes and installation of the outer pin withinanother outer hole of the plurality of outer holes.

A9.1.5.6.4 The assembly of any of paragraphs A9.1.5.6-A9.1.5.6.3,wherein the plurality of outer holes extends helically along a length ofthe outer member.

A9.2 The assembly of any of paragraphs A9-A9.1.5.6.4, wherein the outermember defines an outer flange that extends radially inward from theinner surface of the outer member, and further wherein the outer stopstructure includes the outer flange.

A9.2.1 The assembly of paragraph A9.2, wherein the outer flange isintegral to the outer member.

A9.2.2 The assembly of any of paragraphs A9.2-A9.2.1, wherein the outerflange extends perpendicular to a longitudinal axis of the outer member.

A9.2.3 The assembly of any of paragraphs A9.2-A9.2.2, wherein the outerflange defines a shoulder-opposed surface.

A9.2.3.1 The assembly of paragraph A9.2.3, wherein the shoulder-opposedsurface extends perpendicular to a/the longitudinal axis of the outermember.

A9.2.3.2 The assembly of any of paragraphs A9.2.3-A9.2.3.1, wherein theouter flange extends from the shoulder-opposed surface to the externalshoulder.

A9.2.4 The assembly of any of paragraphs A9.2-A9.2.3.2, wherein theouter flange defines a shoulder-facing surface.

A9.2.4.1 The assembly of paragraph A9.2.4, wherein the shoulder-facingsurface extends perpendicular to a/the longitudinal axis of the outermember.

A9.2.4.2 The assembly of any of paragraphs A9.2.4-A9.2.4.1, wherein theouter flange extends from the shoulder-facing surface to a drive end ofthe outer member that is opposed to the external shoulder.

A9.2.4.3 The assembly of any of paragraphs A9.2.4-A9.2.4.2, wherein theouter flange extends between the shoulder-facing surface and a/theshoulder-opposed surface of the outer flange.

A9.2.5 The assembly of any of paragraphs A9.2-A9.2.4.3, wherein the stopfurther includes an inner adjustment mechanism that is operativelyattached to the inner member.

A9.2.5.1 The assembly of paragraph A9.2.5, wherein the stop is a/theretraction stop, and further wherein the inner adjustment mechanism isconfigured to operatively contact a/the shoulder-facing surface of theouter flange to restrict motion of the inner member within the elongateinternal cavity in a/the retraction direction.

A9.2.5.2 The assembly of any of paragraphs A9.2.5-A9.2.5.1, wherein thestop is a/the retraction stop, and further wherein the inner adjustmentmechanism is located between a/the shoulder-facing surface of the outerflange and the external shoulder.

A9.2.5.3 The assembly of any of paragraphs A9.2.5-A9.2.5.2, wherein thestop is a/the extension stop, and further wherein the inner adjustmentmechanism is configured to operatively contact a/the shoulder-opposedsurface of the outer flange to restrict motion of the inner memberwithin the elongate internal cavity in a/the extension direction.

A9.2.5.4 The assembly of any of paragraphs A9.2.5-A9.2.5.3, wherein thestop is a/the extension stop, and further wherein the inner adjustmentmechanism is located between a/the shoulder-opposed surface of the outerflange and a/the drive end of the outer member that is opposed to theexternal shoulder.

A9.2.5.5 The assembly of any of paragraphs A9.2.5-A9.2.5.4, wherein theinner adjustment mechanism includes an inner threaded bushing, whereinthe inner stop structure includes an inner threaded region that extendsalong the external surface of the inner member, and further wherein theinner threaded bushing is configured to be threaded into the innerthreaded region via rotation of the inner threaded bushing.

A9.2.5.5.1 The assembly of paragraph A9.2.5.5, wherein the innerthreaded region extends along a longitudinal axis of the elongateinternal cavity.

A9.2.5.5.2 The assembly of any of paragraphs A9.2.5.5-A9.2.5.5.1,wherein the stop is configured to be transitioned among the plurality ofstop configurations via rotation of the inner threaded bushing.

A9.2.5.5.3 The assembly of any of paragraphs A9.2.5.5-A9.2.5.5.2,wherein the stop further includes an inner locking structure configuredto lock the inner threaded bushing at a desired location within theinner threaded region, optionally wherein the inner locking structureincludes an inner lock nut.

A9.2.5.6 The assembly of any of paragraphs A9.2.5-A9.2.5.5.3, whereinthe inner adjustment mechanism includes an inner pin, wherein the innerstop structure includes a plurality of inner holes that is configured toreceive the inner pin, and further wherein the inner pin is configuredto be inserted into a selected one of the plurality of inner holes.

A9.2.5.6.1 The assembly of paragraph A9.2.5.6, wherein the inner pin isan inner set screw, wherein the plurality of inner holes is a pluralityof inner threaded holes, and further wherein the inner set screw isconfigured to be threaded into a selected one of the plurality of innerthreaded holes via rotation of the inner set screw relative to the innermember.

A9.2.5.6.2 The assembly of any of paragraphs A9.2.5.6-A9.2.5.6.1,wherein the plurality of inner holes extends perpendicular, or at leastsubstantially perpendicular to a/the longitudinal axis of the elongateinternal cavity.

A9.2.5.6.3 The assembly of any of paragraphs A9.2.5.6-A9.2.5.6.2,wherein the stop is configured to be transitioned among the plurality ofstop configurations via removal of the inner pin from a given inner holeof the plurality of inner holes and installation of the inner pin withinanother inner hole of the plurality of inner holes.

A9.2.5.6.4 The assembly of any of paragraphs A9.2.5.6-A9.2.5.6.3,wherein the plurality of inner holes extends helically along a length ofthe inner member.

A10. The assembly of any of paragraphs A1-A9.2.5.6.4, wherein the stopis a/the adjustable stop, wherein the stop direction is a first stopdirection, and further wherein the pin tool assembly includes a fixedstop configured to restrict motion of the inner member relative to theouter member in a second stop direction that is opposed to the firststop direction, optionally wherein the first stop direction is one ofan/the extension direction and and/the retraction direction, and furtheroptionally wherein the second stop direction is the other of theextension direction and the retraction direction.

A11. The assembly of any of paragraphs A1-A10, wherein the welding endis a planar welding end.

A12. The assembly of any of paragraphs A1-A11, wherein the welding endis a smooth welding end.

A13. The assembly of any of paragraphs A1-A12, wherein the welding endis a grooved welding end.

A14. The assembly of any of paragraphs A1-A13, wherein the inner memberhas a cylindrical, or at least substantially cylindrical, externalsurface.

A15. The assembly of any of paragraphs A1-A14, wherein a portion of theinner member that projects from the opening is perpendicular, or atleast substantially perpendicular, to the external shoulder.

A16. The assembly of any of paragraphs A1-A15, wherein the externalshoulder is a planar external shoulder.

A17. The assembly of any of paragraphs A1-A16, wherein the externalshoulder is a smooth external shoulder.

A18. The assembly of any of paragraphs A1-A17, wherein the externalshoulder is a grooved external shoulder.

A19. The assembly of any of paragraphs A1-A18, wherein the elongateinternal cavity is a cylindrical, or at least substantially cylindrical,elongate internal cavity.

A20. The assembly of any of paragraphs A1-A19, wherein an externalsurface of the outer member is a cylindrical, or at least substantiallycylindrical, external surface.

A21. The assembly of any of paragraphs A1-A20, wherein the outer memberis a tubular, or at least substantially tubular, outer member.

A22. The assembly of any of paragraphs A1-A21, wherein the outer memberis a hollow cylindrical, or at least substantially hollow cylindrical,outer member.

B1. A friction stir welding apparatus comprising:

the pin tool assembly of any of paragraphs A1-A22;

a drive structure configured to rotate the pin tool assembly about a/thelongitudinal axis of the inner member;

an inner member translation structure configured to selectively vary thedistance between the welding end of the inner member and the externalshoulder of the outer member;

an anvil that defines an anvil surface that is opposed to the weldingend of the inner member; and

a separation regulating structure that is configured to selectively varya distance between the external shoulder of the outer member and theanvil surface.

B2. The friction stir welding apparatus of paragraph B1, wherein theapparatus further includes a control structure configured toautomatically control the operation of at least one of:

(i) the drive structure;

(ii) the inner member translation structure; and

(iii) the separation regulating structure.

C1. A method of operating a friction stir welding apparatus (FSWA), themethod comprising:

locating a workpiece on an anvil of the FSWA, wherein the workpieceincludes a joint between two bodies to be friction stir welded together;

rotating a pin tool assembly of the FSWA;

plunging a welding end of an inner member of the pin tool assembly intothe workpiece;

maintaining an external shoulder of an outer member of the pin toolassembly in contact with an anvil-opposed surface of the workpiece,wherein the outer member defines an elongate internal cavity, andfurther wherein the inner member extends through the elongate internalcavity;

translating the welding end of the pin tool assembly along the joint tofriction stir weld the two bodies together; and

during the translating, restricting motion of the welding end relativeto the external shoulder in a stop direction with a stop, wherein thestop defines a plurality of stop configurations, and further wherein therestricting includes restricting within the elongate internal cavity.

C2. The method of paragraph C1, wherein the method further includesadjusting a distance between the welding end and the external shoulderduring the translating.

D1. A method of operating a friction stir welding apparatus (FSWA), themethod comprising:

determining a desired stop configuration of a plurality of stopconfigurations for a pin tool assembly of the FSWA; and

adjusting a stop configuration of the pin tool assembly to the desiredstop configuration by changing a location of an adjustment mechanism ofthe pin tool assembly, wherein the pin tool assembly includes an outermember, which defines an elongate internal cavity and an externalshoulder, and an inner member, which extends at least partially withinthe elongate internal cavity and defines a welding end that projectsfrom the elongate internal cavity via an opening that is defined withinthe external shoulder, wherein the desired stop configurationcorresponds to a desired distance between the welding end and theexternal shoulder, and further wherein the changing includes modifying arelative orientation at which the inner member, within the elongateinternal cavity, operatively couples to the outer member via theadjustment mechanism.

D2. The method of paragraph D1, wherein the determining is based, atleast in part, on a thickness of a workpiece that is to be friction stirwelded by the FSWA.

D3. The method of any of paragraphs D1-D2, wherein the adjustingincludes rotating a threaded bushing of the pin tool assembly.

D4. The method of any of paragraphs D1-D3, wherein the adjustingincludes locating a set screw of the pin tool assembly within a selectedone of a plurality of threaded holes of the pin tool assembly.

E1. The method of any of paragraphs C1-D4, wherein the pin tool assemblyincludes the pin tool assembly of any of paragraphs A1-A22.

E2. The method of any of paragraphs C1-E1, wherein the friction stirwelding apparatus includes the friction stir welding apparatus of any ofparagraphs B1-62.

As used herein, the terms “selective” and “selectively,” when modifyingan action, movement, configuration, or other activity of one or morecomponents or characteristics of an apparatus, mean that the specificaction, movement, configuration, or other activity is a direct orindirect result of user manipulation of an aspect of, or one or morecomponents of, the apparatus.

As used herein, the terms “adapted” and “configured” mean that theelement, component, or other subject matter is designed and/or intendedto perform a given function. Thus, the use of the terms “adapted” and“configured” should not be construed to mean that a given element,component, or other subject matter is simply “capable of” performing agiven function but that the element, component, and/or other subjectmatter is specifically selected, created, implemented, utilized,programmed, and/or designed for the purpose of performing the function.It is also within the scope of the present disclosure that elements,components, and/or other recited subject matter that is recited as beingadapted to perform a particular function may additionally oralternatively be described as being configured to perform that function,and vice versa. Similarly, subject matter that is recited as beingconfigured to perform a particular function may additionally oralternatively be described as being operative to perform that function.

The various disclosed elements of apparatuses and steps of methodsdisclosed herein are not required to all apparatuses and methodsaccording to the present disclosure, and the present disclosure includesall novel and non-obvious combinations and subcombinations of thevarious elements and steps disclosed herein. Moreover, one or more ofthe various elements and steps disclosed herein may define independentinventive subject matter that is separate and apart from the whole of adisclosed apparatus or method. Accordingly, such inventive subjectmatter is not required to be associated with the specific apparatusesand methods that are expressly disclosed herein, and such inventivesubject matter may find utility in apparatuses and/or methods that arenot expressly disclosed herein.

As used herein, the phrase, “for example,” the phrase, “as an example,”and/or simply the term “example,” when used with reference to one ormore components, features, details, structures, embodiments, and/ormethods according to the present disclosure, are intended to convey thatthe described component, feature, detail, structure, embodiment, and/ormethod is an illustrative, non-exclusive example of components,features, details, structures, embodiments, and/or methods according tothe present disclosure. Thus, the described component, feature, detail,structure, embodiment, and/or method is not intended to be limiting,required, or exclusive/exhaustive; and other components, features,details, structures, embodiments, and/or methods, including structurallyand/or functionally similar and/or equivalent components, features,details, structures, embodiments, and/or methods, are also within thescope of the present disclosure.

1. A method of operating a friction stir welding apparatus (FSWA), themethod comprising: locating a workpiece on an anvil of the FSWA, whereinthe workpiece includes a joint between two bodies to be friction stirwelded together; rotating a pin tool assembly of the FSWA; plunging awelding end of an inner member of the pin tool assembly into theworkpiece; maintaining an external shoulder of an outer member of thepin tool assembly in contact with an anvil-opposed surface of theworkpiece, wherein the outer member defines an elongate internal cavity,and further wherein the inner member extends through the elongateinternal cavity; translating the welding end of the pin tool assemblyalong the joint to friction stir weld the two bodies together; andduring the translating, restricting motion of the welding end relativeto the external shoulder in a stop direction with a stop, wherein thestop defines a plurality of stop configurations, and further wherein therestricting includes restricting within the elongate internal cavity. 2.The method of claim 1, wherein the rotating the pin tool assemblyincludes at least one of: (i) rotating the pin tool assembly relative tothe workpiece; (ii) rotating the pin tool assembly with a drivestructure of the FSWA; (iii) rotating the outer member of the pin toolassembly; (iv) rotating the inner member of the pin tool assembly; (v)rotating the external shoulder; and (vi) rotating the welding end. 3.The method of claim 1, wherein the plunging includes translating thewelding end and the workpiece into contact with one another.
 4. Themethod of claim 1, wherein the plunging includes at least one of: (i)operatively deforming the workpiece with the welding end; (ii) heatingthe workpiece via friction between the workpiece and the welding end;and (iii) mechanically mixing the workpiece via rotation of the weldingend.
 5. The method of claim 1, wherein the plunging includes utilizing aseparation regulating structure to selectively vary a distance betweenthe external shoulder of the outer member and the anvil.
 6. The methodof claim 1, wherein the maintaining includes regulating a normal forcethat is applied to the workpiece by the pin tool assembly to maintainthe external shoulder in contact with the workpiece.
 7. The method ofclaim 1, wherein the maintaining includes maintaining during therotating and subsequent to the plunging.
 8. The method of claim 1,wherein the translating includes mechanically intermixing a portion ofeach of the two bodies that is proximal to the joint.
 9. The method ofclaim 1, wherein the translating includes translating during therotating and during the maintaining.
 10. The method of claim 1, whereinthe restricting includes restricting during the translating.
 11. Themethod of claim 1, wherein the method further includes adjusting adistance between the welding end and the external shoulder during thetranslating.
 12. The method of claim 11, wherein the adjusting includesselectively adjusting the distance between the welding end and theexternal shoulder to change a depth to which the welding end plungesinto the workpiece.
 13. The method of claim 11, wherein the adjustingincludes selectively adjusting the distance between the welding end andthe external shoulder based, at least in part, on a thickness of theworkpiece.
 14. The method of claim 11, wherein the adjusting includesadjusting during the translating.
 15. The method of claim 1, wherein thestop extends at least partially within the elongate internal cavity. 16.A method of operating a friction stir welding apparatus (FSWA), themethod comprising: determining a desired stop configuration of aplurality of stop configurations for a pin tool assembly of the FSWA;and adjusting a stop configuration of the pin tool assembly to thedesired stop configuration by changing a location of an adjustmentmechanism of the pin tool assembly, wherein the pin tool assemblyincludes an outer member, which defines an elongate internal cavity andan external shoulder, and an inner member, which extends at leastpartially within the elongate internal cavity and defines a welding endthat projects from the elongate internal cavity via an opening that isdefined within the external shoulder, wherein the desired stopconfiguration corresponds to a desired distance between the welding endand the external shoulder, and further wherein the changing includesmodifying a relative orientation at which the inner member, within theelongate internal cavity, operatively couples to the outer member viathe adjustment mechanism.
 17. The method of claim 16, wherein thedetermining is based, at least in part, on a thickness of a workpiecethat is to be friction stir welded by the FSWA.
 18. The method of claim16, wherein the adjusting includes rotating a threaded bushing of thepin tool assembly.
 19. The method of claim 16, wherein the adjustingincludes locating a set screw of the pin tool assembly within a selectedone of a plurality of threaded holes of the pin tool assembly.
 20. Themethod of claim 16, wherein the adjustment mechanism extends at leastpartially within the elongate internal cavity.